The Respiratory Distress Observation Scale: are three minutes necessary?
The purpose of this study was to compare the differences in scoring results on the Respiratory Distress Observation Scale (RDOS) at one minute versus three minutes when evaluating the cognitively impaired adult patient on mechanical ventilation.
Background
According to the American Thoracic Society the Respiratory Distress Observation Scale (RDOS) is currently the only scale that can objectively score respiratory distress in the cognitively impaired adult. However, this scale is relatively new and has not been extensively evaluated for validity and reliability across populations.
Research performed in 2008 and 2010 regarding RDOS validity and reliability testing utilized only a 3 minute observation period. For use in clinical practice, a shorter observation period is practical. Other observational scales that are used on adults in critical care are validated for scoring in as little as 30 seconds, such as the Richmond Agitation and Sedation Scale (RASS) and the Glasgow Coma Scale.
Methods
This study was an observational study in which the 2008 RDOS scoring was completed on cognitively impaired medical intensive care patients on mechanical ventilation. This study took place in a 24 bed medical intensive care unit at a large metropolitan hospital. Mechanically ventilated subjects were pre-screened for levels of cognition. Patients with psychiatric related diagnoses were excluded. Scoring was completed within 5 minutes that included a one minute and then a 3 minute period or alternatively a 3 minute then one minute period. This study was approved by the hospital’s Institutional Review Board.
Results
52 subjects with a total of 133 paired observations were analyzed for correlation. t-test results showed a significant correlation at a level of p< 0.001. Post hoc power analysis for two-tailed paired t-testing revealed a power level of 1.0. Utilizing the Pearson’s product moment correlation test, the correlation between the three minute and one minute observation period for the RDOS was highly significant, with r(131) = .80, p <0.001.
Discussion/Implications
For the 2008 RDOS, a one minute observation period is essentially as good as a 3 minute observation period. For busy clinicians, an RDOS requiring less time is more likely to be used in clinical practice in the intensive care unit for adults.